Data available for 1994-1996, and for 2006. Data is cross-sectional whereas patient information cannot be followed over time; longitudinal comparisons between the two time periods of data may be broadly made for trends in procedural rates of other ambulatory surgical characteristics. The NSAS is not currently active; however information about ambulatory surgical visits may be included in the future as a function of the National Hospital Ambulatory Medical Care Survey (NHAMCS).

After downloaded, dataset user-friendly for researchers versed in appropriate use of statistical software. NCHS staff helpful in accommodating users.

Data analysis

Data is weighted to produce estimates. Publication of estimates is based on the relative standard error of the estimate and the number of sample records on which the estimate is based (the sample size). Estimates are not presented in NCHS reports unless a reasonable assumption regarding the probability distribution of the sampling error is possible. If the sample size is 60 or more and the relative standard error is less than 30 percent, the estimate is reported.

Pros

Sole national study of ambulatory surgical care in the US. Survey sampling designed to represent national surgical utilization (as opposed to other surgical databases which represent convenience samples of participating facilities).

Cons

Most recent data is from 2006 which may not reflect current trends in healthcare administration and policy. Only assesses patients who undergo surgery, therefore need for surgery, magnitude of symptoms, as well as diagnostic and referral criteria for treatment cannot be assessed. High missing rates of race and ethnicity variables; socioeconomic variables limited (no information on household income or poverty level). Many otolaryngological procedures represent only a portion of ambulatory surgery and therefore have low un-weighted sample sizes, reducing statistical reliability for meaningful comparisons.